At least 2 million people are infected by these bacteria, including MRSA and Clostridium difficile, every year, according to the Centers for Disease Control and Prevention. More than 23,000 people die as a direct result, and many more die from associated complications.

These bacteria have evolved this way because they've been exposed so frequently to antibiotics and antibacterial substances, that they developed genes to protect themselves from these compounds.

Alcohol is an antiseptic agent that kills most bacteria on external surfaces on contact, breaking down ALL OF the proteins that make up bacteria and some viruses. (Bleach works similarly, but is much more potent — don't put that directly on your hands.)

Antibiotics, meanwhile, typically target specific aspects of bacteria, and don't just work on external surfaces.

Instead of shattering down a door like a sledge hammer the way alcohol does, antibiotics are more like keys that fit into very specific keyholes: When they click together, the bacteria are destroyed.

Because alcohol attacks all proteins in the bacteria, not just one, the bacteria can't develop resistance.

When to wash

They don't work as well if hands are visibly dirty or greasy however, and so handwashing is recommended in those circumstances — but not with antibacterial soap, which usually has an ingredient called triclosan that may make the problem of antibiotic resistance worse.

Plain old soap and cool water will do, as well. Actually, handwashing is a more effective way to remove some bacteria in the first place, which is why people should still wash their hands regularly.

The tricky triclosan

AP

There's one big BUT when discussing hand sanitizers: They can contain the antibiotic compound triclosan or triclocarban. This is often found in soaps and even toothpaste. But its prevalence can make bacteria immune.

First of all, there's no evidence that triclosan is effective at preventing illness in the first place, according to the FDA — so it already doesn't do the one thing that it theoretically should.

But even worse, the FDA says research suggests triclosan may lead to hormonal problems and cause bacteria to adapt to its antimicrobial properties, creating more antibiotic-resistant strains. Additional research shows that people with high levels of triclosan in their noses were twice as likely to carry disease-causing Staph bacteria in the nose.

The real problem creating superbugs

When we take antibiotics to treat an infection, the antibiotic-resistant bacteria are the only ones that survive. They pass on their resistant traits, creating whole strains of resistant bacteria. With enough of these mutations, these bugs can be impossible to kill.